Method for manufacturing a face-to-face pile fabric

Abstract: Method for manufacturing a face-to-face pile fabric in which in each case a first weft thread (6) is provided in the top fabric (TF) and the bottom fabric (BF) next to two second and third weft threads (7, 8) located one above the other, and in which in each case three weft threads are inserted simultaneously, each warp thread system comprising binder warp threads (3, 4) and a tension warp thread (9, 10), and pile-forming pile warp threads (11-14) interlacing in accordance with a three-pick weave. The quality of the fabrics (TF, BF) is improved by: in each case forming pile on the first weft thread (6) which is provided on the back of the second (7) and third weft thread (8); binding in the dead pile warp thread (11-16) distributed over both fabrics (TF, BF); in each case forming pile on the third weft thread (8) located on the back while a pile thread which starts forming pile or finishes forming pile is first interlaced with a third weft thread before it starts forming pile or is bound in; binding in the first weft thread (6) by means of binder warp threads (3, 4) in each case in a separate opening (49', 50', ...; 49'', 50'', 49''', 50''',...); in each case forming pile on the first weft thread (6) which is not provided on the back of the fabrics (TF, BF); providing two tension warp threads (9, 10); (9', 10') in each warp thread system.

Description: The present invention relates to a method for manufacturing a face-to-face pile fabric, in which a top fabric and a bottom fabric are formed by providing successive groups of three weft threads for each fabric, so that, in every group, a first weft thread extends next to a second and a third weft thread, which are located one above the other, by providing, for each fabric, adjacent warp thread systems having two binder warp threads which cross a number of times so as to form successive openings between their points of intersection, through which extends in each case a group of weft threads, and by binding a tension warp thread into each fabric in each of the warp thread systems; in each case three weft threads are inserted simultaneously; in accordance with a three-pick weave, in each of the warp thread systems at least one pile-forming pile warp thread is interlaced with a weft thread, alternately in the top fabric and in the bottom fabric; and all pile-forming pile warp threads between both fabrics are cut through in order to obtain two separate pile fabrics. Such a method is known from FR-2.182.790. According to this known method, the pile-forming pile warp threads are in each case interlaced with the third weft threads located on the back of the fabrics (except in case of a change of pile). In each case, two weft threads are inserted simultaneously into one fabric and one weft thread into the other fabric, a weaving loom thus inserting six weft threads in two working cycles. According to this method, the dead pile warp threads (i.e. the pile warp threads or parts of pile warp threads which do not form pile) are alternately bound into the top fabric and into the bottom fabric in the successive warp thread portees (a warp thread portee consists of a warp thread system of the top fabric and a warp thread system of the bottom fabric, whose binder warp threads, tension warp threads and pile warp threads are located one above the other). After the face-to-face fabric has been cut through, each fabric comprises successive rows of pile loops which have been interlaced with corresponding weft threads. These pile loops have upright pile sides. In order to achieve perfect pile formation, these pile sides have to extend at right angles to the plane of the backing fabric (which comprises weft threads, binder warp threads and tension warp threads). If this is not the case (i.e. with a so-called drawn pile), a fabric of inferior quality is obtained. As a result of a drawn pile, mixing contours may occur in the fabrics. If the pile sides form different colour fields in a pile fabric (in order to produce a design or pattern), mixing contours occur when pile sides of a different colour are visible among pile sides of one colour on the pile surface of the fabrics. This is caused as a result of pile sides of one colour extending at an angle among the pile sides of another colour in the vicinity of the separation line between two colour fields, and being visible at the pile surface of the fabric. The colours mix and the fabrics have no clearly defined separation line between adjacent colour fields. The fabric produced according to the method of FR-2.182.790 exhibits a drawn pile. It is an object of this invention, to provide a method for manufacturing a face-to-face pile fabric by means of which a drawn pile is prevented while binding in the dead pile warp threads in each warp thread portee distributed over both fabrics. It was found that the drawn pile was a result of the fact that the first weft threads penetrate the second and third weft threads lying above one another. The upright sides of the pile loops therefore tend to spread out, thereby not remaining in the desired upright position as the face-to-face pile fabric is cut through. The abovementioned object is achieved by a method as described in the first paragraph of this description, wherein the first weft threads of successive groups extend in a first plane, which lies on the back relative to a second and third plane in which, respectively, the second and third weft threads of these successive groups extend, wherein the pile-forming pile warp threads are in each case interlaced with a first weft thread, and wherein the dead pile warp threads are bound in in each warp thread portee, distributed over both fabrics. Thus, two weft threads (the second and third weft threads), one above the other, are located in each case on either side of a pile loop. These weft threads keep the pile sides upright. In addition, the first weft thread is prevented from penetrating the second and third weft threads located above one another. As a result, the pile sides remain in the desired position, after the face-to-face pile fabric is cut through, at right angles to the plane of the backing fabric, so that a drawn pile no longer occurs. Furthermore, the quality of the fabrics is also improved as the dead pile warp threads are bound in in each warp thread portee distributed over both fabrics. With the known method according to FR-2.182.790, the pile warp threads which finish forming pile are interlaced with a second weft thread in a first warp thread portee before they are bound into the top fabric, and the pile warp threads which start forming pile are interlaced with a third weft thread before they start to form pile (run to the bottom fabric). In a second warp thread portee, the pile warp threads which finish forming pile are interlaced with a third weft thread before they are bound into the bottom fabric, and the pile warp threads which start forming pile are interlaced with a second weft thread before they start forming pile (run to the top fabric). The face-to-face pile fabric has alternating first and second warp thread portees. In each fabric, there are thus pile warp threads which interlace with second weft threads (located on the side of the pile). The pile sides thus formed are not visible on the back of the fabrics. The pattern of the pile fabrics is thus not completely visible on the back of the fabrics. Moreover, the visible part of the pattern appears as a dashed line. An additional object of this invention is to produce the complete pattern of the pile fabrics clearly on the back of the fabrics. If, in the known method, the dead pile warp threads were to be bound in distributed over both fabrics, this would lead to mixing contours. When a first pile warp thread which was bound into one fabric starts forming pile (runs to the other fabric) and a second pile warp thread which was forming pile runs to said other fabric in order to be bound into the latter, both pile warp threads jointly run between both fabrics. This causes mixing contours after the face-to-face pile fabric is cut through. In order to prevent mixing contours, it should be ensured that, with the pile warp threads which have a pile-forming part which changes into a bound-in part and/or a bound-in part that changes into a pile-forming part, a last or a first pile side, respectively, of said pile warp threads remains upright relative to the backing fabric after the fabrics have been cut through. Mixing contours are prevented and the complete pattern of the pile fabrics appears clearly on the back by means of interlacing a pile warp thread with a first weft thread, before said pile warp thread is bound in or starts forming pile, respectively. In this manner, said first and last pile sides are also laterally supported by weft threads located one above the other, after the face-to-face pile fabric has been cut through. The pile sides remain upright, thereby preventing mixing contours. Moreover, each pile side is interlaced with a weft thread on the back, so that the pattern is clearly and completely visible on the back of the fabrics. In a preferred method according to this invention, the tension warp threads are in each case bound in such that they extend between said first and third weft threads. As a result, the dead pile warp threads bound into the fabrics are protected on the back by these tension warp threads. The pile-forming pile warp threads being interlaced with a respective first weft thread running on the back of the tension warp thread, the pattern of the pile fabric is very accurate and clearly visible on the back of the pile fabrics. A fabric (in particular, a carpet) which is weaved according to a three-pick weave tends to curl towards the back. This is caused by the fact that, on the one hand, the pile warp thread bound in on the back prevents the elongation or extension of the fabric on the back, while, on the other hand, the bound-in dead pile warp threads push the fabric apart on the pile side. Moreover, the weft threads situated on the pile side of the dead pile warp threads may push these dead pile warp threads between successive weft threads against the tension warp threads, as a result of which dead pile warp treads are bound in in a wave-like manner and causing increased pile consumption. An additional object of this invention is to eliminate these disadvantages. This object is achieved in that a second tension warp thread is provided for every warp thread system in each fabric. This second tension warp thread is bound in between the second and third weft threads so that only the second weft threads extend on the pile side of this second tension warp thread. The first tension warp thread extends between the first and third weft threads of every warp thread system. As a result of this second tension warp thread, the fabric can not extend on the pile side and curling is prevented. In addition, the weft threads running on the pile side can not press the dead pile warp threads against the first tension warp threads. The dead pile warp threads remain extended and pile consumption for binding in remains at a minimum. When using two tension warp threads in every warp thread system, the warp threads of a warp thread system can be arranged next to one another in the following order: the first tension warp thread, the two binder warp threads, the second tension warp thread, the pile warp threads. The pile warp threads are thus in each case situated between two tension warp threads (the second tension warp thread of a warp thread system and the first tension warp thread of a subsequent warp thread system). The pile sides are consequently out of range of the binder warp threads, so that these binder warp threads cannot affect the orientation of the pile sides. Thus the pile sides assume the desired upright position and form straighter lines in the warp direction on the pile surface. This results in the pile sides not mixing with pile sides of an adjacent row of pile loops. Furthermore, an additional tension warp thread may serve as a guide for the weft insertion means so that dead pile warp threads do not have to carry a weft insertion means which could result in them being damaged or breaking as a consequence of their contact with a weft insertion means. By binding in the dead pile warp threads in such a manner that they extend between the second and third weft threads and extend on the pile side of the fabric relative to the first weft threads, the bound-in dead pile warp threads do not show through on the back of the pile fabrics, resulting in an identical appearance of the back of both pile fabrics. (After all, pile warp threads that are bound into the top fabric differ in colour from the pile warp threads that are bound into the bottom fabric). It is important that, in the above-described methods according to this invention, double pile warp threads do not occur. Double (married) pile warp threads occur when a pile change is effected (when a first pile warp thread which formed pile from a certain pick onwards is bound in and a second pile warp thread which was bound in starts forming pile from the same pick onwards) in the face-to-face fabric, between a first pile warp thread which is to be bound into one fabric after the pile change and a second pile warp thread which was bound into the other fabric before the pile change. The marriage of these pile warp threads between top fabric and bottom fabric results in so-called mixing contours (a pile side in one coloured area extends into another colour field) causing poor delineation on the pile surface between adjacent colour fields. This is prevented by omitting a pile loop, or in other words by either binding the first pile warp thread into the pile fabric two picks earlier than the fixed pick or the second pile warp thread starting to form pile two picks later than the fixed pick. The pile warp thread whose pile loop is omitted is set so that the omission takes place in the direction where there is more than one pile loop. The method according to this invention can be implemented to great effect, using a triple weft insertion mechanism with which, alternately, a second and third weft thread are provided in the bottom fabric and a first weft thread in the top fabric, and a second and third weft thread in the top fabric and a first weft thread in the bottom fabric, respectively. In a particularly preferred method according to this invention, the second and/or the third weft thread of each group, is (are) thinner than the first weft thread of that group. The pile-forming pile warp threads of a group are thus interlaced in each case with a relatively thick weft thread while one or both of the other weft threads of the group are relatively thin. This results in the pattern becoming visible even more clearly on the back, and the colour of the bound-in dead pile warp threads not showing through on the back. Thus, both pile fabrics have an identical back which clearly shows the pattern. The characteristics of the method according to this invention are explained in the following description of a face-to-face pile fabric manufactured in accordance with this method. In this description, reference is made to the attached figures, in which: Figure 1 shows a cross section of the face-to-face pile fabric, manufactured according to this invention; Figure 2 shows a diagrammatic representation of the positions of the tension warp threads, binder warp threads and pile warp threads relative to the three weft insertion means of a triple weft insertion mechanism during weaving according to the invention of a face-to-face pile fabric having two tension warp threads for each fabric, on a face-to-face weaving loom; According to the method of this invention, a face-to-face pile fabric is manufactured by forming a top fabric (TF) and a bottom fabric (BF). Both fabrics (TF, BF) are formed by providing for each fabric in each case successive groups of three weft threads (6, 7, 8), so that, in every group, a first weft thread (6) extends next to a second (7) and a third weft thread (8), which are located one above the other, and by providing, for each fabric (TF, BF), adjacent warp thread systems having two binder warp threads (3, 4), one or more tension warp threads (9, 10; 9', 10') and one or more pile warp threads (11, 16). These binder warp threads (3, 4) cross each other a number of times so as to provide successive openings (49-55) between their points of intersection, through which extend in each case a group of weft threads (6, 7, 8). In this manner, the weft threads (6, 7, 8) are bound into the respective fabrics (TF, BF). The tension warp threads (9, 10;, 9', 10') are bound into the respective fabrics (TF, BF) in each of the warp thread systems. The pile-forming pile warp threads (11-13) are interlaced with a first weft thread (6) alternately in the top fabric (TF) and in the bottom fabric (BF) in accordance with a three-pick weave. Dead pile warp threads (14 -16) are bound into one of the fabrics (TF, BF). A pile warp thread (11 - 13) may have a part which forms pile and another part which may be bound in as dead pile warp thread. The face-to-face pile fabric is manufactured on a face-to-face weaving loom provided with a triple weft insertion means (21, 22, 23, in Figure 2), by means of which in each case three weft threads (6, 7, 8) are inserted simultaneously. In a first operating cycle, a second (7) and a third weft thread (8) are inserted into the top fabric (TF) and a first weft thread (6) is inserted into the bottom fabric (BF). In a second (subsequent) operating cycle, a first weft thread (6) is inserted into the top fabric (TF) and a second (7) and third weft thread (8) are inserted into the bottom fabric (BF). By inserting six weft threads (6, 7, 8) in two working cycles of the weaving loom, very efficient weaving is achieved. In accordance with a this invention, a face-to-face carpet is manufactured, in which the first weft threads (6) are provided in a plane on the back relative to the two planes above one another, through which the second (7) and third weft threads (8), respectively, extend. The binder warp threads (3, 4) cross a number of times and form successive openings (49-55) through which extend in each case a second (7) and a third weft thread (8), one above the other, followed by a first weft thread (6). In each fabric (TF, BF), in every warp thread system, a first tension warp thread (9, 10) is bound in which extends between the first weft threads (6) and the third weft threads (8). Furthermore, in each fabric (TF, BF), in every warp thread system, a second tension warp thread (9', 10') is bound in which extends between the second (7) and third weft threads (8). The dead pile warp threads (11-16) are bound in, divided over both fabrics (TF, BF), and extend between the second (7) and third weft threads (8). The pile-forming pile warp threads (11-13) are in each case interlaced with the first weft threads (6). After the face-to-face fabric has been cut through (cf. diagrammatic representation of cutting means in Figure 1), the pile sides are supported by the second (7) and third weft threads (8) which extend next to one another. In this manner, an upright pile is produced and mixing contours are prevented. The first tension warp thread (9, 10) protects the dead pile warp threads (11-16) on the back of the carpet. Since only the first weft threads (6), on which pile is formed, extend on the back of the first tension warp thread (9, 10), the pattern is very clearly visible on the back of the carpet. The dead pile warp threads can be prevented from showing through on the back of the carpet by means of the first tension warp threads (9, 10). The pattern is represented in full on the back of the carpet because a pile warp thread (12, 13) is interlaced with a first weft thread (6) at the transition from a bound-in part to a pile-forming part, before it starts forming pile, and because a pile warp thread (11, 12) is interlaced with a first weft thread (6) at the transition from a pile-forming part to a bound-in part, before it is bound in. When manufacturing a face-to-face pile fabric (TF), (BF) according to the method according to this invention by means of a face-to-face weaving loom having a triple weft insertion mechanism (see Figure 2), the binder warp threads (3, 4), the tension warp threads (9, 10), (9', 10') and the pile warp threads (11-16) are taken to a level prior to every pick (or shot) relative to the respective weft insertion heights of the three weft insertion means (21, 22, 23) of the triple weft insertion mechanism such that these threads (3, 4, 9, 9', 10, 10', 11-16), after the insertion of the weft threads (6, 7, 8), extend in the top fabric (TF) and the bottom fabric (BF), in the position required according to the desired weave relative to the weft threads (6, 7, 8). The warp threads (3, 4, 9, 9', 10, 10', 11-16) extend through the reed (20). After the weft threads (6, 7, 8) have been inserted, they are pushed by the reed (20) to the edge of the face-to-face pile fabric (TF), (BF) already formed. In this case, the binder warp threads (3, 4) and the tension warp threads (9, 10), (9', 10') are positioned, for example, by means of heald frames, while the pile warp threads (11-16) are positioned by means of a jacquard mechanism. The triple weft insertion mechanism alternately inserts two weft threads (7, 8) into the top fabric (TF) and one weft thread (6) into the bottom fabric (BF), and two weft threads (7, 8) into the bottom fabric (BF) and one weft thread (6) into the top fabric (TF), respectively. The top weft insertion means (21) alternately inserts a weft thread (6) and a weft thread (8) into the top fabric (TF). The bottom weft insertion means (23) alternately inserts a weft thread (8) and a weft thread (6) into the bottom fabric (BF). The centre weft insertion means (22) alternately inserts a weft thread (7) into the bottom fabric (BF) and a weft thread (7) into the top fabric (TF). In the method according to this invention, in which two tension warp threads (9, 10), (9', 10') are provided for each fabric (TF), (BF), the tension warp threads (9', 10') serve as a guide for the weft insertion means (21, 22, 23). In the situation illustrated in Figure 2, the tension warp thread (9) of the top fabric (TF), the tension warp thread (10') of the bottom fabric (BF) and the tension warp thread (10) of the bottom fabric (BF) form a guide for the top (21), centre (22) and bottom (23) weft insertion means, respectively. Thus, the dead pile warp threads (11-14) do not have to fulfil this guide function and they are prevented from being damaged or breaking.

Claims: Method for manufacturing a face-to-face pile fabric, in which a top fabric (TF) and a bottom fabric (BF) are formed by providing successive groups of three weft threads (6, 7, 8) for each fabric (TF, BF), so that, in every group, a first weft thread (6) extends next to a second (7) and a third weft thread (8), which are located one above the other, by providing, for each fabric (TF, BF), adjacent warp thread systems having two binder warp threads (3, 4) which cross a number of times so as to form successive openings between their points of intersection, through which extends in each case a group of weft threads (6, 7, 8), and by binding a tension warp thread (9, 10) into each fabric (TF, BF) in each of the warp thread systems; in each case three weft threads are inserted simultaneously; in accordance with a three-pick weave, in each of the warp thread systems at least one pile-forming pile warp thread (11-14) is interlaced with a weft thread (6), alternately in the top fabric (TF) and in the bottom fabric (BF); and all pile-forming pile warp threads (11-14) between both fabrics (TF, BF) are cut through; characterized in that the first weft threads (6) of successive groups extend in a first plane, which lies on the back relative to a second and third plane in which, respectively, the second (7) and third weft threads (8) of these successive groups extend; in that the pile-forming pile warp threads (11-14) are in each case interlaced with a first weft thread (6); and in that dead pile warp threads (11-16) are bound in in each warp thread portee, distributed over top fabric (TF) and bottom fabric (BF). Method according to Claim 1, characterized in that a pile warp thread (11-13) whose pile-forming part changes into a bound-in part is interlaced with a first weft thread (6) before it is bound in, and/or in that a pile warp thread (11-13) whose bound-in part changes into a pile-forming part is interlaced with a first weft thread (6) before it starts forming pile. Method according to claim 1 or 2, characterized in that the tension warp threads (9, 10) extend between said first (6) and third weft threads (8). Method according to Claim 3, characterized in that a second tension warp thread (9', 10') is bound in in each warp thread system between the second (7) and third weft threads (8) so that only the second weft threads (7) extend on the pile side of the second tension warp thread (9', 10'). Method according to one of the preceding claims, characterized in that a tension warp thread (9, 10), (9', 10') on either side of the pile warp threads (11-16) of each warp thread system. Method according to Claim 4 or 5, characterized in that at least one of the tension warp threads (9, 10) (9', 10') of a warp thread system is used as support for a weft insertion means (21), (22), (23). Method according to one of the preceding claims, characterized in that the dead pile warp threads (11-16) are bound in between the second (7) and third weft threads (8) and extend on the pile side of the fabric (TF, BF) relative to the first weft threads (6). Method according to one of the preceding claims, characterized in that, in order to effect a pile change - at a particular pick in the face-to-face fabric - between a first pile warp thread, which is to be bound into one fabric (TF or BF) after the pile change, and a second pile warp thread which was bound into the other fabric (BF or TF) before the pile change, the marriage of these pile warp threads between top fabric (TF) and bottom fabric (BF) is prevented by either binding the first pile warp thread into the pile fabric (TF, BF) two picks earlier than said particular pick or by allowing the second pile warp thread to start forming pile two picks later than said particular pick. Method according to one of the preceding claims, characterized in that alternately, a second (7) and third weft thread (8) are provided in the bottom fabric (BF) and a first weft thread (6) in the top fabric (TF), and a second (7) and third weft thread (8) in the top fabric (TF) and a first weft thread (6) in the bottom fabric, respectively, using a triple weft insertion means. Method according to one of the preceding claims, characterized in that the second (7) and/or the third weft thread (8) of each group is (are) thinner than the first weft thread (6) of that group.

Inventors: DEWISPELAERE ANDRE, GHEYSEN NICO, MERTENS JOS, DEWISPELAERE, ANDRE, GHEYSEN, NICO, MERTENS, JOS, Dewispelaere, André
Applicants: WIELE MICHEL VAN DE NV, N.V. MICHEL VAN DE WIELE
Application year: 1994
Main classification: D03D27
IPC codes: D03D27